Rue de Rivoli is one of Paris' main boulevards. It passes by city hall, the Louvre museum, and also the Tour Saint Jacques- originally the steeple of a church built in the 16th century.

These days, the tower's covered in a white shell. In May the top was uncovered. Gargoyles stare down to the street below, and if you strain your eyes, you can see hints of intricate detail on the walls

In 2006, the city of Paris embarked on a massive restoration of the tower. It was literally falling into pieces. Emilie Masse is a restorer who worked on the tower this summer. She gives a tour of the worksite

We start at the top, accessible by elevator in scaffolding

At the top, Masse points out the statues:

There is Saint Jacques, or Saint James- surrounded by the Tetramorph, or the symbols of four evangelists:

The Bull of Saint Luke, Saint Marc's lion, Saint John's Eagle, and the angel of Saint Matthew.

The walls are covered with intricately carved animals, flowers and geometric shapes. All this 30 meters up in the air- barely visible from the ground.

Before anything can be restored or repaired, the stones must be cleaned. They are black with soot and pollution. Masse explains that they're cleaned by micro-abrasion—streams of fine sand to blast off the encrusted dirt

Some things can't be cleaned with this method, though- because it's too corrosive. So they use lasers.

Masse makes the sound of the laser. It's a beam, a couple of millimeters thick that dislodges the dirt. Many of the stones are being replaced with new ones. They are measured, then taken out. Stone carvers like Lucien Mazet cut them to size:

He explains that the site has no machines. Everything is done old fashioned, with hand tools—chisels...

...and hand saws

Once the stones are fit into the wall, the sculptors carve the details. They study the old ones, and come up with an appropriate replacement.

Joel Duvignacq is in charge of this restoration and maintenance Paris' cultural and historical buildings.

The tower was the steeple of a 16th century church. During the Revolution the church was dismantled, but the steeple was saved. In the 1850s, during the Baron Haussmann's massive renewal of Paris, the tower was turned into a landmark, and a public garden was built around the base. All that, plus several renovations during the 20th century- The sculptors have a lot of eras to think about:

The stones that aren't replaced are restored:

Emilie Masse shows one that hasn't been worked on yet.

It crumbles in as she brushes it with her hand. She explains there are cracks where water can get in which, when it freezes, will crack the stone even more.

Masse explains that to restore a stone, she first removes all the lose bits. Then the stone is impregnated with a glue to bind it, and the surface is covered with a protective mortar.

The project budget is eight million euros, funded half by the city, and half by the state. Expensive, yes, but important, says Duvignacq [translation]:

Today, if you go into the garden at the base of the tower, you can look through windows onto the worksite

The renovations will run until spring of 2009. The scaffolding will be progressively removed, top down, and the tower will gradually emerge.